1. Field of the Invention
The present invention relates to a method for mounting components and a component mounter adopting the method. More particularly, the present invention relates to a component mounter which comprises a plurality of head units for receiving various kinds of components from a component supply apparatus, transferring them to a mounting position of a printed circuit board (PCB), and mounting them to the PCB.
2. Description of the Related Art
As shown in FIG. 1, a conventional component mounter 1 comprises a head unit 4 having at least one nozzle 5, an X axis transfer mechanism 3, and Y axis mechanisms 2. The nozzle 5 vertically moves to absorb or detach electronic components and mount them to PCB P. The X axis transfer mechanism 3 and the Y axis transfer mechanisms 2 guide the head unit 4 to a predetermined position.
The Y axis transfer mechanisms 2 are arranged parallel at both sides of the bed. The X axis transfer mechanism 3 and a conveyor 6 which carries a printed circuit board (“PCB”) are arranged at a right angle direction to the Y axis transfer mechanisms 2. In this case, both ends of the X axis transfer mechanism 3 move in the Y axis direction while keeping a right angle to the Y axis transfer mechanism 2 because they do not perform a relative movement.
Therefore, in order to mount the electronic components, one end and the other end of the X axis transfer mechanism 3, move in the Y axis direction at the same time, and the head units 4 mounted to the X axis transfer mechanism 3 respectively move in the X axis direction, and thus each head unit 4 is positioned on the PCB P corresponding to the head unit 4. Thereafter, the nozzles 5 descend and mount the electronic components to the PCB. In this case, one end and the other end of the X axis transfer mechanism 3 moving in the Y axis direction are in the same position in the Y axis direction. That is, one end and the other end of the X axis transfer mechanism 3 do not perform a relative movement.
A recent component mounter comprises at least two head units 4 having a plurality of nozzles 5. The plurality of nozzles 5 absorb a plurality of electronic components one by one or at the same time, move a plurality of absorbed electronic components from the conveyor 6 at the same time, and mount the moved electronic components to the PCB P one by one or at the same time, thus increasing efficiency in mounting the components. The trend is toward a plurality of PCBs P being supplied to the conveyor 6, depending on the number of head units.
However, in the component mounter 1, there is a positional difference that occurs when the conveyor 6 is not placed parallel to the X axis when assembling the conveyor 6 or when a plurality of PCBs P are not placed parallel to the conveyor 6 when positioning the PCB P to the conveyor 6. Due to such a positional difference, a Y axis position of one head unit 4 is not the same as that of the PCB P corresponding to the head unit 4 when a Y axis position of the other head unit 4 is equally adjusted to that of the PCB P corresponding to the head unit 4.
Thereby, it is impossible to mount multiple electronic components to the PCB by descending, at the same time, nozzles provided to at least two head units on the component mounter.
To solve such a problem, a position of a portion of the conveyor unit in the Y axis direction may be corrected. However, this method increases a material cost due to the increasing number of shafts and position accuracy deteriorates because a position of the head unit and a position of the conveyor should control at the same time.